I am in the middle of bathroom remodeling. I tried to minimize my work by removing bathtub surrounding walls only. The rest of walls in the original baturoom are there. After I installed wonderboards, I realized the backing columns were not aligned properly. The window side of the wonderboard goes in about 1/2 inch and slope to the joint with the original wall (about 1/8 inch deeper than the original wall). Originally, the surrounding wall was concreat (not boards, but manually built up). I don't want to remove the wonderboard to fix columns. Is there anything I cna apply to the surface of the board to make it flat to the original wall? Would concreate stick to the wonderboard?